Helical Carbon Nanotubes hMWNT

It was not long after the discovery of carbon nanotubes before specimens with coiled or helical shapes were observed. These helical nanotubes (hMWNT) are often found as by-product in the synthesis of multiwalled nanotubes, yet by now a directed preparation has succeeded as well. Their extraordinary shape turns the helical nanotubes into an interesting subject of research as the expected electronic properties like inductive effect under electrical current should enable an application, for example, as nanocoils.  

The production of hMWNT is possible on different ways. For instance, they are the main product of converting pyridine or toluene in a CVD apparatus in a stream of hydrogen at about 1100°C in the presence of iron pentacarbonyl. But also the reduction of diethyl ether at ca. 700 C on zinc yields up to 80% of helical nanotubes. 

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